Not my picture/website, but I still have my very first scientific calculator from when I was really young, and it's one of these. I even still have the faux-leather slipcase it came with: http://www.loreneverly.org/cal013.html

Trouble is, the battery on mine is expired and the solar functon only provides SOME of the power it needs. Without the battery the screen barely shows up at all.

I also discovered one day that if you press all 8 basic function buttons on the right side of the numbers all at once, you can trigger a glitch which forces the thing off, since there's no off button and it takes 5 minutes to turn off on its own.

Yeah, I liked math as a kid. Strange, hunh? ;D

Vacuum Fluorescent Displays.

Fuckin' pimp man. 😁

(Actually, if the numbers are in "individual tubes" then they must be nixie tubes? In which case, even more pimp!)

No, there were individial VFD tubes too... a lot of people mistakenly call them nixies, but they're entirely different.

I've been kinda keeping an eye out for an old nixie calculator, but haven't ever run across one, and I'm not gonna pay eBay prices for 'em.

^ Correct. VFD tubes. I think Nixies were a few years before this calculator's day. Also, some interesting things: the Negative symbol is a red LED and also, each button on the calculator is actually a magnet. Under each, there's a glass tube with two separated pieces of metal. When you press a button, magnet is close enough to the glass tube that the two metal pieces inside connect and make a circuit.

Oh, how I miss my old National Semiconductor 4615 PR programmable RPN calculator:

http://www.rskey.org/CMS/index.php/7?manufact … ctor&model=4615

http://spyropoulos.net/calcs-other/NS4615PR.jpg

Hehe, I can STILL hear all of my classmates from my days back in high school... "WHERE'S THE 'EQUALS' KEY???!!!" 🤣! 😀

GXL750 wrote:

Under each, there's a glass tube with two separated pieces of metal. When you press a button, magnet is close enough to the glass tube that the two metal pieces inside connect and make a circuit.

Reed switch.

Sometime in 1971-73 my dad got me a rechargable scientific calculator for Christmas. It blew me away - I felt like I'd been given a IBM main frame and practically felt unworthy...

I'm pretty sure it was a "Melcor", I remember it being a "Melcor 2000", but a quick net search didn't come up with that model though Melcor was an early pocket calculator manufacturer during those years. It was pretty thick/heavy, black with sort of beveled edges and largish red numbers def not lcd. I think it had some programmable functions. None of the pics I just saw online were the model - If I find it I'll post. It got thrown out about 10 years later. I remember how "The Brain" used to take quite a bit of time to produce answers to complex equations..

Cool thread..

Edit: I just uncovered a Canon "Palmtronic LE-81" in my small collection of old consumer electronics. Dates 73-74, was the mainstay calculator at home for years. Nice fit and feel for simple math. LED.

7-Segment LEDs, I actualy prefer those than the (newer) polarized LCD counterpart.

Somehow I like the 'bright on dark' of the LED more than 'dark on not-so-bright' LCD.
but the problem with that LED is electric current leakage that will makes some of its 'segment' became dim-ly light when its not supposed to.

Early LED displays I don't care for. One example is a Rockwell pocket calculator from the 1970s I own. The display is just too small and doesn't provide good viewing angle.

BTW, I was reading about old TI products and found this page:
http://www.datamath.org/Graphing/TI-78.htm

Has anyone here heard of the Ti 78? It captures my interest. Not quite a calculator, not quite a computer.

I was poking around that www.datamath.org site, and while really not all that old, two calculators that I STILL own (and USE on almost a daily basis):

http://www.datamath.org/Desktop/ti-1795+.htm

http://www.datamath.org/Sci/Modern/TI-35X_1.htm

I don't think a calculator made after solar cells, coin cell batteries and LCDs caught on goes obsolete. I don't see many calculators from the 70s or early 80s in regular use but it seems calculators from the late 80s and up are just as common as brand new ones.

There's also a few models out there that seem to have been designed just right and apparently won't leave production anytime soon. The blue Ti-108 popular in elementary schools and the HP 12C come to mind.

There are two calculators that I use, the rest I just have because I like collecting them. A Ti86 and an HP 12C. I used to have a Ti81 and a Casio graphic calculator that had a color display. I accidentally broke the Ti81 and the Casio I sold because it's display hurt my eyes.

I don't think a calculator made after solar cells, coin cell batteries and LCDs caught on goes obsolete

perhaps because theres not much improvement need to be made for cashier/bussines/sales/non-scientific calculators.

now that i think about it, those calcs have longer 'life-cyle' than modern computers!

I remember with some regret throwing away a perfectly working TI-59 with program packs, manuals and a binder full of cards, about 20 years ago. 😒.

I still use a Sharp EL-506P, a mini sci-calc that slides/stores into a little vinyl book style cover. From the mid-80s still works fine - just needs a coin battery every so often.

Wish I'd saved my slide rules from High School.

Reportedly older RPN calculators (distinguished by the presence of a large ENTER key) can be worth a fair bit of money.

I know HP still manufactures the 12C and if I'm not mistaken, they still manufacture other model calculators that use RPN.